This application is based upon and claims priority of Japanese Patent Application No. 2001-194823, filed on Jun. 27, 2001, the contents being incorporated herein by reference.
1. Field of the Invention
The present invention relates to a plasma display and a method of driving the same.
2. Description of the Related Art
FIG. 11 is a diagram showing the basic configuration of a plasma display panel device. A control circuit portion 1101 controls an addressing driver 1102, a common electrode (X electrode) sustaining circuit 1103, a scanning electrode (Y electrode) sustaining circuit 1104, and a scanning driver 1105.
The addressing driver 1102 supplies predetermined voltages to addressing electrodes A1, A2, A3, . . . , Hereinafter, the addressing electrodes A1, A2, A3, . . . are respectively or generally called addressing electrodes Aj, and xe2x80x9cjxe2x80x9d means a subscript.
The scanning driver 1105 supplies predetermined voltages to scanning electrodes Y1, Y2, Y3, . . . according to the control of the control circuit portion 1101 and the scanning electrode sustaining circuit 1104. Hereinafter, the scanning electrodes Y1, Y2, Y3, . . . are respectively or generally called scanning electrodes Yi, and xe2x80x9cixe2x80x9d means a subscript.
The common electrode sustaining circuit 1103 supplies the same voltage to common electrodes X1, X2, X3, . . . respectively. Hereinafter, the common electrodes X1, X2, X3, . . . are respectively or generally called common electrodes Xi, and xe2x80x9cixe2x80x9d means a subscript. The respective common electrodes Xi are connected to one another and have the same voltage level.
In a display region 1107, the scanning electrodes Yi and the common electrodes Xi form rows extending in parallel in a horizontal direction, and the addressing electrodes Aj form columns extending in a vertical direction. The scanning electrodes Yi and the common electrodes Xi are arranged alternately in the vertical direction. A stripe rib structure in which ribs 1106 are arranged between the addressing electrodes Aj is provided.
The scanning electrodes Yi and the addressing electrodes Aj form a two-dimensional matrix composed of i rows and j columns. Display cells Cij are formed by intersections of the scanning electrodes Yi and the addressing electrodes Aj and the common electrodes Xi adjacent to the intersections correspondingly. The display cells Cij correspond to pixels, and thereby the display region 1107 can display a two-dimensional image.
FIG. 12A is a diagram showing the sectional structure of the display cell Cij in FIG. 11. The common electrode Xi and the scanning electrode Yi are formed on a front glass substrate 1211. Attached thereon is a dielectric layer 1212 to insulate them against a discharge space 1217, and further attached thereon is an MgO (magnesium oxide) protective film 1213.
Meanwhile, the addressing electrode Aj is formed on a back glass substrate 1214 disposed facing the front glass substrate 1211, and attached thereon is a dielectric layer 1215, and further attached thereon is a phosphor. Ne+Xe Penning gas or the like is sealed in the discharge space 1217 between the MgO protective film 1213 and the dielectric layer 1215.
FIG. 12B is a diagram for explaining a capacity Cp of an alternating current drive type plasma display. A capacity Ca is the capacity of the discharge space 1217 between the common electrode Xi and the scanning electrode Yi. A capacity Cb is the capacity of the dielectric layer 1212 between the common electrode Xi and the scanning electrode Yi. A capacity Cc is the capacity of the front glass substrate 1211 between the common electrode Xi and the scanning electrode Yi. The capacity between the electrodes Xi and Yi is determined by the total of these capacities Ca, Cb, and Cc.
FIG. 12C is a diagram for explaining glowing of the alternating current drive type plasma display. On the inner face of the rib 1216, red, blue, and green phosphors 1218 are respectively arranged and applied in a stripe pattern, and light 1221 is generated by exciting the phosphors 1218 by discharge between the common electrode Xi and the scanning electrode Yi.
FIG. 13 is a schematic diagram of one frame FR of an image. The image is composed of, for example, 60 frames per second. The one frame FR is composed of a first subframe SF1, a second subframe SF2, . . . , and a n-th subframe SFn. This xe2x80x9cnxe2x80x9d is, for example, 10 and corresponds to the number of tone bits. The subframes SF1, SF2, and so on are respectively or generally called subsrames SF hereinafter.
Each subframe SF is composed of a reset period Tr, an addressing period Ta, and a sustaining period (sustaining discharge period) Ts. During the reset period Tr, the display cells are initialized. During the addressing period Ta, whether to light or not to light the respective display cells can be selected according to address designation. The selected cell glows during the sustaining period Ts. The number of times of glowing (glowing time) differs from one SF to another. Thereby, the tone value can be determined.
FIG. 14 shows a driving method during the sustaining period Ts of a progressive mode plasma display according to a prior art. At a point in time t1, an anode potential Vsa is applied to common electrodes Xnxe2x88x921, Xn, and Xn+1, and a cathode potential Vsb is applied to scanning electrodes Ynxe2x88x921, Yn, and Yn+1. Thereby, high voltage is applied respectively between the common electrode Xnxe2x88x921 and the scanning electrode Ynxe2x88x921, between the common electrode Xn and the scanning electrode Yn, and between the common electrode Xn+1 and the scanning electrode Yn+1 to generate sustaining discharges 1410.
Subsequently, at a point in time t2, the cathode potential Vsb is applied to the common electrodes Xnxe2x88x921, Xn, and Xn+1, and the anode potential Vsa is applied to the scanning electrodes Ynxe2x88x921, Yn, and Yn+1. Thereby, high voltage is applied respectively between the common electrode Xnxe2x88x921 and the scanning electrode Ynxe2x88x921, between the common electrode Xn and the scanning electrode Yn, and between the common electrode Xn+1 and the scanning electrode Yn+1 to generate the sustaining discharges 1410.
Thereafter, at a point in time t3, the sustaining discharges 1410 are generated by applying the same potentials as at the point in time t1, and at a point in time t4, the sustaining discharges 1410 are generated by applying the same potentials as at the point in time t3.
FIG. 15 shows a driving method during the sustaining period Ts of an ALIS (Alternate Lighting of Surfaces) mode plasma display according to the prior art. At the point in time t1, the anode potential Vsa is applied to the common electrodes Xnxe2x88x921 and Xn+1 in odd-numbered lines, and the cathode potential Vsb is applied to the scanning electrodes Ynxe2x88x921 and Yn+1 in odd-numbered lines. Then, the cathode potential Vsb is applied to the common electrode Xn in an even-numbered line, and the anode potential Vsa is applied to the scanning electrode Yn in an even-numbered line. Thereby, high voltage is applied respectively between the common electrode Xnxe2x88x921 and the scanning electrode Ynxe2x88x921, between the common electrode Xn and the scanning electrode Yn, and between the common electrode Xn+1 and the scanning electrode Yn+1 to generate sustaining discharges 1510.
Subsequently, at the point in time t2, the cathode potential Vsb is applied to the common electrodes Xnxe2x88x921 and Xn+1 in the odd-numbered lines, and the anode potential Vsa is applied to the scanning electrodes Ynxe2x88x921 and Yn+1 in the odd-numbered lines. Then, the anode potential Vsa is applied to the common electrode Xn in the even-numbered line, and the cathode potential Vsb is applied to the scanning electrode Yn in the even-numbered line. Thereby, high voltage is applied respectively between the common electrode Xnxe2x88x921 and the scanning electrode Ynxe2x88x921, between the common electrode Xn and the scanning electrode Yn, and between the common electrode Xn+1 and the scanning electrode Yn+1 to generate the sustaining discharges 1510.
Thereafter, at the point in time t3, the sustaining discharges 1510 are generated by applying the same potentials as at the point in time t1, and at the point in time t4, the sustaining discharges 1510 are generated by applying the same potentials as at the point in time t3.
FIG. 16 shows an abnormal operation of excessive lighting during the sustaining period Ts. A case where a pair of the electrodes Xn and Yn is address-designated and a pair of the electrodes Xnxe2x88x921 and Ynxe2x88x921 and a pair of the electrodes Xn+1 and Yn+1 are not address-designated is shown. When the plasma display is in normal operation, a discharge is generated between the address-designated electrodes Xn and Yn. As a result, the display cell with the electrodes Xn and Yn is lighted, and the display cell with the electrodes Xnxe2x88x921 and Ynxe2x88x921 and the display cell with the electrodes Xn+1 and Yn+1 are not lighted.
In some cases, however, the display cells are not completely initialized due to poor initialization or the like during the reset period Tr (FIG. 13). Consequently, an unnecessary wall charge sometimes remains at the electrode Ynxe2x88x921 or Xn+1. Thereby, a discharge is erroneously generated between the electrodes Yn and Xn+1 or between the electrodes Xn and Ynxe2x88x921. As a result, a discharge is generated between the electrodes Xn+1 and Yn+1 or between the electrodes Xnxe2x88x921 and Ynxe2x88x921, whereby unnecessary excessive lighting occurs.
FIG. 17 shows an abnormal operation in which a display cell which should be lighted is not lighted during the sustaining period Ts. A case where the pair of the electrodes Xn and Yn, the pair of the Xnxe2x88x921 and Ynxe2x88x921, and the pair of the electrodes Xn+1 and Yn+1 are address-designated is shown. When the plasma display is in normal operation, all of the display cell with the electrodes Xn and Yn, the display cell with the electrodes Xnxe2x88x921 and Ynxe2x88x921, and the display cell with the electrodes Xn+1 and Yn+1 are lighted.
In some cases, however, the display cells are not completely initialized due to poor initialization or the like during the reset period Tr (FIG. 13). As a result, although discharges should be originally generated between the electrodes Xn+1 and Yn+1 and between the electrodes Xnxe2x88x921 and Ynxe2x88x921, discharges are sometimes erroneously generated between the electrodes Xn+1 and Yn and between the electrodes Ynxe2x88x921 and Xn. Consequently, an abnormal operation, in which the display cell with the electrodes Xn+1 and Yn+1 and the display cell with the electrodes Xnxe2x88x921 and Ynxe2x88x921 are not lighted, occurs.
With the advance of high definition of the plasma display and an increase in the number of pixels, the adjacent display cells come closer to each other, and the influence of discharge interference increases, whereby the aforementioned problems remarkably arise. Although the ribs 1106 are provided between the addressing electrodes Aj in FIG. 11, partitions are not provided in the vertical direction in FIG. 11, and hence discharge interference in the vertical direction is prone to occur.
Generally, as shown in FIG. 16 and FIG. 17, the interval of a slit between the electrodes Xn and Yn between which a sustaining discharge is generated is narrowed, and the interval of a slit between the electrodes Yn and Xn+1 (Ynxe2x88x921 and Xn) between which a sustaining discharge is not generated is widened, whereby discharges are separated, but when high definition advances as described above, the interval between the adjacent display cells can not be fully secured.
An object of the present invention is to provide a plasma display capable of a stable sustaining discharge by a reduction in the influence of adjacent display cells and a method of driving the same.
According to an aspect of the present invention, there is provided a plasma display, wherein a plurality of first display electrodes and a plurality of second display electrodes are arranged in parallel with one another, and a plurality of addressing electrodes are arranged to intersect the first and the second display electrodes, and wherein a driver for applying a potential lower than an anode potential and higher than a cathode potential to the first and the second display electrode adjacent to the first and the second display electrode between which a sustaining discharge is generated when the sustaining discharge is generated between the first and the second display electrode by applying the anode potential to one of the first and the second display electrode and the cathode potential to the other thereof is provided.
By applying the anode potential to one of the first and the second display electrode and the cathode potential to the other thereof, the sustaining discharge can be generated between the first and the second display electrode. On this occasion, by applying the potential lower than the anode potential and higher than the cathode potential to the first and the second display electrode adjacent to the first and the second electrode between which the sustaining discharge is generated, a display cell in which the sustaining discharge is generated can prevent a bad influence from a display cell adjacent thereto.